The accompanying data represent the pulse rates (beats per minute) of nine students. treat the nine students as a population. compute the z-scores for all the students. compute the mean and standard deviation of these z-scores.

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.